Headbox for twin wire paper making apparatus

ABSTRACT

A HEADBOX FOR USE IN A TWIN WIRE VERTICAL PAPER MAKING MACHINE COMPRISING A DOWNWARDLY EXTENDING SLICE HAVING ELONGATED PARALLEL SIDE WALLS WHICH FORM THE STOCK INTO A HIGH SPEED JET DIRECTED INTO THE AREA BETWEEN TWIN BREAST ROLLS. ONE OF THE LIPS OF THE SLICE IS ADJUSTABLE IN SUCH A MANNER THAT IS ALWAYS REMAINS PARALLEL TO THE OPPOSITE LIP SO THAT THE THICKNESS OF THE JET CAN BE VARIED WITHOUT THE CREATION OF TURBULENCE OR PRESSURE VARIATION WITHIN THE JET AS IT IS FORMED BETWEEN THE LIPS. IN ANOTHER EMBODIMENT, ONE SLICE LIP IS SIMULTANEOUSLY ADJUSTED WITH ONE BREAST ROLL TO CHANGE THE WIDTH OF THE FORMING ZONE AND THE SLICE AT THE SAME TIME.

2 Sheet-Sheet 1 j -w.vc. NCTBQHM ET AL .BEADBox FORTWIN WIRE PAPER MAKING APPARATUS:-

Filed Feb. 6; 1968 May 11, 10o

United States Patent 3,578,560 HEADBOX FOR TWIN WIRE PAPER MAKING APPARATUS Willard C. Notbohm, Charles A. Lamb, and J. Leslie Hanson, Water-town, N.Y., assignors to The Black Clawson Company, Hamilton, Ohio Filed Feb. 6, 1968, Ser. No. 703,299 Int. Cl. D21f 1/06 US. Cl. 162-344 11 Claims ABSTRACT OF THE DISCLOSURE A headbox for use in a twin wire vertical paper making machine comprising a downwardly extending slice having elongated parallel side walls which form the stock into a high speed jet directed into the area between twin breast rolls. One of the lips of the slice is adjustable in such a manner that it always remains parallel to the opposite lip so that the thickness of the jet can be varied without the creation of turbulence or pressure variation within the jet as it is formed between the lips. In another embodiment, one slice lip is simultaneously adjusted with one breast roll to change the width of the forming zone and the slice at the same time.

BACKGROUND OF THE INVENTION The headbox of this invention is adapted for use on a paper making machine generally of the type shown in Baxter Patent No. Re. 25,333, granted Feb. 19, 1963, and characterized by the incorporation of a pair of endless forming wires or webs arranged to travel substantially vertically in closely spaced relation thereby creating a forming zone wherein the paper sheet or web is formed. The invention is also related to the invention shown in Green Patent No. 3,215,593, granted Nov. 2, 1965, wherein the paper stock is supplied to the forming zone by a headbox arranged to flood the nip between the breast rolls and allow the wires to draw as much stock into the forming zone as the space between the wires will permit. Both of these patents are assigned to the assignee of this invention.

It has been found that some types of paper making stock and at increased production speeds, it is desirable to avoid flooding the space above the nip and to feed the stock directly into the forming zone at substantially the speed of the wires to prevent entrapment of air within the stock of the forming zone. It is also important with some paper making stocks to minimize the internal volume of the headbox so that large quantities of stock do not dwell therein sufiiciently long to result in settling or separation tending to cause nonuniformity in the paper sheet. A headbox of this general type is shown and described in the copending application of Rojecki, Ser. No. 660,083, filed Aug. 11, 1967, also assigned to the assignee of this application.

The requirements for providing adjustability in the amount of stock being fed between the forming wires as well as the speed thereof must be carefully regulated if the machine is to be adapted to produce paper of different weights and composition, and at different speeds. Any adjustment of the parallel lips of the slice presents difliculties because it must not create turbulence or cross flow which would disturb the desired thickness or uniformity of the jet of stocks as it passes from the lips to the forming zone.

SUMMARY OF THE INVENTION The present invention is accordingly directed to an improved headbox wherein the paper making stock is directed downwardly into the forming zone between gradually converging forming wires traveling at paper machine speed. The headbox has a slice opening provided between parallel lips which shape the stock flow into an elongated jet of preset uniform thickness. The invention is more particularly directed to mechanism for moving one of the lips of the headbox parallel to the opposite lip so that the thickness and velocity of the jet can be varied as required.

The mechanism for adjusting one of the lips includes a linkage in the form of a parallelogram, with one of the links being the movable lip so that regardless of the adjustment, the movable lip always remains in an essentially vertical plane. The other of the lips may be provided with separate adjusting means along its entire length for the purpose of deforming the lip slightly to compensate for irregularities in the thickness of the paper which is being created. In another form of the invention, at least one of the lips of the slice is coupled to one of the breast rolls so that a change in the distance between the breast rolls and the forming wires creates a proportional change in the width of the slice, and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary view, partly in elevation and partly in section, showing a headbox in accordance with the invention;

FIG. 2 is a sectional view of the headbox taken centrally therethrough;

FIG. 3 is a fragmentary side view of the headbox showing the side of the headbox adjacent one end thereof; and

FIG. 4 is a fragmentary end view illustrating a modified form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The paper machine of FIG. 1 is generally of the type disclosed in Baxter Patent No. Re. 25,333, and includes the improved headbox 10 in accordance with this invention which delivers stock to then nip 11 between the pair of breast rolls 12 and 13. Couch rolls 14 and 15 are positioned in parallel relation below the breast rolls 12 and 13, and the corresponding breast and couch'rolls have forming Webs or wires 16 and 17 entrained therearound so that a vertical forming zone is defined between these wires. The forming wires move downwardly from the nip 11 into the forming zone in a gradually converging path guided by supporting deflectors 18 which exert a squeezing action on the stock between the wires to expel the white water therefrom through the wires into a suitable collection pan from where it is returned to the white water supply system. These defiectors are preferably of the type described in the copending application Ser. No. 711,583, filed of even date herewith and assigned to the assignee of this invention.

The headbox 10 is supported on the machine frame 19 and extends across the width of the frame above and co extensive in length with the nip 11 between the breast rolls. It includes an enclosed housing defining a pressure chamber 21 having side walls 22 and sloping bottom walls 23 converging downwardly to a series of vertical tubes 24 which conduct the stock into the V-shaped chamber 25 with maximum uniformity as described in Notbohm Pat. No. 3,328,237, granted to the assignee of this invention. Stock is supplied to the pressure chamber 21 of the headbox from the inlet manifold 26 which extends along the right hand side of the headbox and has a gradually decreasing cross-section, as shown in FIG. 3.

. A series of connector pipes 27 are closely spaced along the entire length of the manifold 26 to connect the interior thereof to the interior of the pressure chamber 21 of the headbox 10. The gradually decreasing section of the manifold 26 insures that the pressure of the stock supplied to each of the pipes 27 is substantially identical in accordance with present practices in the paper making art. A perforated rectifier roll 30 is mounted for rotation in the pressure chamber 21 immediately above the entrance to the vertical tubes 24 for evenly distributing the flow into these tubes and for creating eddy currents of relatively small magnitude immediately adjacent the inlet ends of the tubes for the dual purpose of minimized flocculation in the stock and preventing clogging or plugging of the tubes 24. This rotor is mounted on suitable bearings 32 at the opposite end walls 33 of the headbox and is driven by a motor 34 connected to the rotor through the gear box 35.

The V-shaped receiving chamber 25 (FIG. 2) of the headbox 10 is defined by the tapering side walls 37 and 38 which have the parallel lips 41 and 42 mounted at the lower ends thereof to provide a slice outlet passage 44 in which a jet of stock is formed and forced into the nip 11 and the space between the wires 16 and 17. Both the walls 37 and 38 and the lips 41 and 42 extend across the entire width of the paper machine, and the end walls 45 on the opposite ends' thereof are secured to the flanges 46 on the adjacent end walls 33 of the headbox 10 by conventional fasteners 47, as shown in FIG. 3. A suitable seal 48 is provided between the opposite ends of the slice lips and the adjacent end walls 45 to prevent leakage of stock therebetween.

The right-hand side wall 37 and slice lip 41 (FIG. 2) are movable with respect to the stationary left-hand Wall 38 and lip 42 to permit changes in the width of the slice passage 44. Thus the movable side wall 37 is pivotally secured by the hinge 50 to the lower bracket portion 51 of the bottom wall 53. This hinge includes a cylindrical rod 54 rigidly fastened along the top edge of the side wall 37 parallel to the width of the machine and is received in the complementary depression 55 formed in the flange 56 and the retainer 58 secured to the flange 56 by the screws 59. The retainer 58, which extends across the width of the machine, together with the flange 56 and close more than one-half of the rod 54 and thus retains it in position while permitting rotation about the axis of the rod.

The movable lip 41 is pivotally secured to the lower end of the movable side wall 37 by a hinge 60 similar to the hinge 50 just described. Accordingly, the hinge 60 includes a cylindrical rod 62 secured along the entire upper edge of the movable lip 41 and received in the complementary depression 64 in the bracket 65. When the retainer 66 is clamped in place on the bracket 65 by the screws 67, more than one-half of the rod 62 is enclosed so that it is held in place for angular movement only.

The movable slice lip 41, which extends downwardly with the inner surface 70- thereof parallel to the inner surface 71 of the stationary lip 42, is moved by linkage in the form of a parallelogram. which maintains the surfaces 70 and 71 parallel regardless of the width of the slice passage 44 therebetween. This linkage includes an L-shaped bracket 73 which extends upwardly from a rigid connection with the lip 41 to a cross member 74 extending across the width of the machine above the right-hand breast roll 12. Movement of the bracket 73 is guided by the link 75, which extends downwardly from a pivot connection 76 with the rigid extension 77 on the headbox 10 to a similar pivot connection 78 with the bracket 73, as shown in FIG. 1. The distance between the pivot connections 76 and 78 is identical to the distance between the hinges 50 and 60, and the distance between the hinge 50- and the upper pivot connection 76 is identical to the distance between the hinge 60 and the lower pivot connection 78 to create a parallelogram which prevents angular movement of the slice lip 41 so that the inner surface 70 thereof always remains substantially parallel to the inner surface 71 of the stationary slice lip 42.

Movement of the support bracket 73, and thus of the movable lip 41, is controlled by a turnbuckle 80 having one screw 84 pivoted at 81 to the headbox structure and its second screw 84 pivoted at 82 to the bracket 73. Rotation of the adjusting nut 85 causes movement of the screws 84 toward and away from each other in the usual way to eifect adjusting movement of the lip 41 as it is moved by the parallelogram linkage described. A lockriut 87 holds the turnbuckle in each desired adjusted position.

The stationary slice lip 42 can be deformed slightly at localized points along its length for the purpose of compensating for slight irregularities in the slice opening, by means of a series of deforming levers 90 (FIG. 2) spaced along the width of this stationary lip. Each lever 90 is mounted on the lower portion of the rigid side wall 38 of the V-shaped chamber 25 by a pivot pin 91 connected to the support bracket 92. The lowermost end of each lever 90 is connected to the lower portion of the stationary lip by a lower bracket 94 and pivot pin '95 so that vertical movement of the actuator rod 97 effectively deforms the portion of the lip adjacent the lower bracket 94. Each actuator rod 97 is connected by a yoke 98 and pivot pin 99 to its lever 90, and the actuator rods extend upwardly along the side wall 20 of the headbox to suitable actuators 100 of a conventional type which can be operated manually or automatically.

In operation, the headbox 10 supplies a jet of stock to the space between the twin forming wires 16 and 17 as they move downwardly through the nip 11. The stock is supplied to the headbox 10 from the supply manifold 26 by the connector tubes 27 which lead to the pressure chamber 21 of the headbox. The stock then flows through the rotating perforated rectifier rotor 30 into the small diameter tubes 24 which lead to the V-shaped receiving chamber 25. From this chamber, the stock flows under pressure between the parallel lips 41 and '42- of the slice passage 44 which form the stock into a jet of uniform thickness extending coextensively with the wires 14 and 15.

If it is desired to produce a paper of increased weigh it is merely necessary to rotate the actuator nut 85 on the turnbuckle 80 in the appropriate direction so that the support brackets 73 for the movable lip 41 are moved to the right or left, as viewed in FIG. 2, Because the linkage which supports the movable lip 41 is in the form of a parallelogram, the inside surface 70 of the movable lip 41 always remains essentially parallel to the surface 71 of the stationary lip so that the width of the slice passage 44 is always substantially uniform thereby eliminating turbulence and providing a jet of uniform thickness.

' When the slice lip 41 is moved to increase the width of the slice, the wall 37 of the V-shaped receiving chamber 25 also moves about the hinge 54 so that the chamber 25 is enlarged to accommodate the increased width of the slice passage 44. Similarly, when the width of the slice passage 44 is decreased by moving the actuator nut 85 and the support bracket in the opposite direction, the wall 37 moves to decrease slightly the volume of chamber 25.

Another embodiment of the invention is shown in FIG. 4 wherein the slice lips 41 and 42 are identical to those described above. Similarly, the support bracket 73 and parallelogram linkage for the movable slice lip 41 are also identical to those described above, and each of these parts is given the same reference character. In this embodiment, however, the support bracket 73 for the movable lip 41 is connected to adjustable support mechanism 105 for moving the right-hand breast roll 12a so that when this breast roll is moved to increase or decrease the distance between the forming wires 16 and 17, the width of the slice passage 44 is automatically moved a proportionate amount.

Accordingly, the bearing block 107 which supports the shaft 108 of the breast roll 12a is mounted on the machine frame 110 for movement toward and away from the forming zone, as viewed in FIG. 4. The adjustment screw 111 extends through the upstanding block 112 on frame 110 and into an internally threaded bore on the bearing block 107 so that rotation of the hand wheel 114 moves the bearing block 107 toward and away from the opposite stationary breast roll 13. The support mechanism 105 includes identical components on the opposite end of the movable breast roll 12a, and apparatus may be provided for moving the bearing blocks on both sides of the breast roll 12a simultaneously from one actuator to eliminate any possibility of misalignment.

An actuator arm 115 extends upwardly from a rigid connection with the bearing block 107 and has a vertically slotted opening 117 therein which receives the pin 118 connected to the bracket 73. Thus horizontal movement of the bearing block 107 imparts similar movement to the support bracket 73 causing the movable lip 41 to move with the movable breast roll 12a and produce a corresponding change in the width of the slice passage 44 as described above. The parallelogram linkage insures that the lip 41 always remains parallel to the stationary lip 42.

While a particular type of mechanism has been shown in FIG. 4 it should be understood that other structure can be used without departing from the scope of the invention. Suitable linkage may be provided so that the distance moved by the movable lip 41 is less than the distance moved by the breast roll 12, or vice versa, although the change in this distance would be proportional. Similarly, it is possible to adjust both breast rolls 12 and 13 in a horizontal plane with corresponding movement of one or both of the lips 41 or 42 of the slice passage 44.

The invention has thus provided an improved headbox for a twin wire vertical paper making machine which allows the amount of stock being fed between the forming zone to be increased or decreased while maintaining the slice lip substantially parallel so that a jet of uniform thickness throughout is created. Movement of the lip so that the inner surface thereof is parallel to the inner surface of the stationary lip is insured by a parallelogram linkage which includes the side wall of the receiving chamber and the movable lip as two of the links. The lip may be moved manually by a suitable mechanical or other type of actuator, and may be connnected to one or both of the breast rolls for movement.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparaus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A head box for delivering a jet of paper stock between converging moving forming webs of a paper making machine, comprising a housing defining a stock chamber adapted to contain stock under pressure, a pair of slice lips mounted on said housing, said lips having inner planar surfaces arranged in a substantially parallel relationship defining a slice outlet passage for receiving stock under pressure from said stock chamber and for creating a stream of stock of uniform thickness which is directed between the forming webs, and adjustment means for changing the distance between said planar surfaces of said slice lips while maintaining said substantially parallel relation therebetween to make corresponding changes in the thickness of the stream of stock being formed therebetween.

2. A headbox as defined in claim 1 wherein said adjustment means includes linkage in the form of a parallelogram which restricts movement of at least one of said lips so that the inner surface thereof remains substantially parallel to the inner surface of the other of said lips in all adjusted positions thereof.

3. A headbox as defined in claim 1 wherein a pair of breast rolls are mounted immediately below said headbox, and said adjusting means includes means for simultaneously changing the distance between said breast rolls in proportion to the change of distance between said lips.

4. A headbox as defined in claim 3 comprising adjustable support means for one of said breast rolls, and means connecting said adjustable support means with said movable slice lip for simultaneous movement of said one breast roll and said movable lip.

5. A headbox as defined in claim 1 comprising a receiving chamber disposed below said stock chamber and including a pair of side Walls, and slice lips being mounted on the lower ends of said side walls, one of said side walls being movable and having a first pivotal connection to said housing, and one of said slice lips being movable and having a second pivotal connection to said one side wall for movement therewith.

6. Apparatus as defined in claim 5 wherein said adjusting means includes a bracket member secured to said movable lip, a link of preset length extending between a third pivotal connection on said housing and a fourth pivotal connection on said bracket member, the distance between said first and second connections being identical to the distance between said third and fourth pivotal connections, and the distance between said first and third pivotal connections being identical to the distance between said second and fourth pivotal connections to insure that said movable slice lip remains parallel to the other of said slice lips.

7. A headbox as defined in claim 5 wherein said first pivotal connections include an elongated cylindrical rod secured to one of said side wall or housing, and retainer means on the other of said side wall or housing secured to said rod for pivotal movement of said side wall with respect to said housing.

8. A headbox as defined in claim 5 wherein a plurality of parallel small diameter tubes interconnect said pressure chamber and said receiving chamber.

9. A headbox as defined in claim 5 wherein said receiving chamber is V-shaped and said side walls converge downwardly, said slice lips secured on the lower end of said side walls and extending downwardly in parallel relation with each other.

10. A headbox as defined in claim 9 wherein one of said side walls and its associated said lip are stationary, comprising a series of spaced lever means each connected to the lower edge of said stationary slice lip having a pivotal connection with said stationary side wall, and an actuator means connected to said lever means for rotating said lever means about said pivot connections to create localized deformation in said stationary slice lip to compensate for minor variations in the thickness of the finished sheet.

11. A headbox for delivering a sheet-like jet of paper making stock to the forming zone of a two-wire paper machine, comprising a stock chamber having inlet means for receiving stock, tube assembly means forming a portion of the bottom of said chamber and providing a plurality of small outlet passages from said chamber, walls depending from said chamber in converging relation to define a flow passage of generally triangular section having the larger end thereof directly connected with said tube assembly means for receiving and intermingling the 7 flows from said tube assembly means, a pair of slice lips depending from the lower edges of said converging walls and having opposed planar surfaces arranged in substantially parallel relation defining an outlet passage of substantial length from said triangular passage, and means for adjusting the distance between said lips while maintaining said lips with said planar surfaces in said substantially parallel relation across the Width of said machine.

References Cited UNITED STATES PATENTS 8 r 3,309,264 3/1967 Parker et al. l62-338X 3,440,436 4/1969 Nelson et al. 16-2-203X FOREIGN PATENTS 1,047,952 11/1966 Great Britain 162343 REUBEN FRIEDMAN, Primary Examiner T. A. GRANGER, Assistant Examiner U.S. Cl. X.R. 

